Treatment of hydrocarbon oils



April 28, 1942. J. D. sEGUY v TREATMENT OF HYDRCARBON OILS Filed Dec. 12, 1938 2 Sheets-Sheet 1 April 28, 1942. Y J. n. sac-UY l TREATMENT'OF HYDROCARBON OILS 2 sheets-sheet 2 Filed Dec. l2, 1938 y W .Nm 1/ ROYURNM) yay yf a

Patented Apr. 28, 1942 TREATMENT OF HYDROCARBON OILS Jean Delattre Seguy, Chicago, Ill., assgnor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application December 12, 1938, Serial No. 245,152

7 Claims.

This invention relates to processes applicable to the treatment of crude petroleums which contain appreciable proportions of gasoline', intermediate fractions and heavy non-volatile residua.

It is more specifically concerned with a method of operation involving a combination of inter-related steps aimed at the ultimate production of optimum yields of high octane number gasoline and specification fuel oil or coke. The various steps involve a primary non-cracking distillation to `produceian overhead cut-'fa number of intermediate cuts and a residuum, each fraction thereafter being treated either pyrolytically or catalytically according to its chemical and physical properties to produce a maxlmum yield of the desired high antiknock gasoline and specification fuel oil or coke.

In one specific embodiment the present invention comprises fractionating crude petroleum to produce an overhead gasoline, light and heavy intermediate fractions and residuum, thermally reforming said light intermediate fraction, ca talytically cracking the heavy intermediate fraction, commingling the residual liquids produced in each of the above operations and thermally cracking the same to produce additional yields of gasoline and either specification fuel oil or coke, While producing gasoline of at least '70 octane number at all points.

The attached diagrammatic drawings show by the use of conventional figures in general vside elevation and without reference to any particular absolute or relative scale, an arrangement of interconnected units in which the process may be conducted.

Referring to the drawing, line I containing valve 2 indicates a charge line for the admission of crude oil to fractionator 3. In this primary step vof the process the incoming material is heated by conventional means not shown to a temperature and under a pressure' sufficient to effect a primary rough fractionation. The pressure used may vary from atmospheric to approximately 100 pounds per square inch and the temperature will vary from approximatelyy 500 to 750 F. The type and character of the fractionating column may be varied to suit the needs of any particular crude oil since all of these materials vary widely with respect totheir boiling characteristics and content of overhead gasoline, intermediate fractions andresidual constituents.

In the drawing, overhead vapor line 4 containing valve 5 preferably leads the vapors of the natural gasoline content of the crude oil to y condensing and cooling equipment not shown. In accordance with the invention, the 'primary fractionating column is operated so that the overhead gasoline has an octane number of at least 70 when tested by the Motor method. This will obviously vary the end-point of this fraction since naphthenic base crudes will permit the use of end-points of 400 F. or higher in each fraction while in the case of highly paraiiinic crudes, such as those from Pennsylvania or Michigan, this end-point will need to be reduced materially if 70 octane numberr product is to be` obtained.

Fractions of crude oil, icomprising the relatively heavy ends of gasoline and the illuminating oil distillates, are preferably taken as a side cut from fractionating column 3 through line 6` containing valve I and directed to a pyrolytc reforming unit by pump 8 which discharges through line 9 containing valve I0 and leading to line II and thence to heating element I2 arranged in furnace I3. The reforming unit is preferably operated at pressures within the range of 500 to 1000 pounds or more per square inch and coil outlet temperature of 1000 to 1l00 F., the heated products pass through line I4' containing valve I5 to a reaction chamber I6 provided to permit additional time 'for the completion of the desired reactions, the total cracked products then passing through line I1 containing valve I8 to a separator I9 which operates at a reduced pressure of the order of 50 to 100 pounds per square inch and whereinvapors separate from residual liquid. The latter is withdrawn from the separator through line 20 and valve 2| for further treatment as will be subsequently described.

The Vaporous conversion products pass through line 22 containing valve 23 to fractionator 24 wherein gasoline boiling range material is separated from heavier products, the latter being condensed as reflux condensate.The reflux condensate may be withdrawn from the lower portion of the fractionator through line 25 containing valve 26 to pump 2'I by means of which it may be returned through line 28 containing valve 29 to line II and thence to coil I2 for further conversion. When it is not desired to return the reux condensate to the heating coil, it may be commingled with the residual` liquid withdrawn from separator I9 through line 20 by well known means not illustrated, or'may be utilized as a'cooling medium for the hot conversion products discharged from the heating coil. Fractionated vapors ci the desired end-boiling point,

2 apetece and xed gases are withdrawn from the upper portion of fractionator 2t through line 25' containing valve 2E' and passed to condenser 2l', from which condensed liquids and uncondensed gases follow line 28' containing valve 2S' to receiver lill having a nxed gas release line 3l containing valve 32 and a gasoline draw line 33 containing valve 38. This unit is preferably operated in conformity with the general subject of the invention so that gasoline of at least 7U octane number is produced. The gas mixture evolved through line 3l may be subjected to polymerization processes to produce gasoline boiling range polymers and augment the yield and quality of the total gasoline produced in the process.

As an alternative method of operation, included within thescope of this invention, separator I9 may be operated to edect a. fairly accurate separation of gasoline boiling range material and residual products. The gasoline boiling range material may then be withdrawn through line 22 into fractionator 26, which would preferably operate as a stabilizing column, the final gasoline product being withdrawn from the lower portion thereof and fixed gases being withdrawn from the upper portion thereof.

Devices such as temperature regulating means between separator i9 and fractionator 2l, the reiiuxing system for controlling the overhead from fracticnator 24 and other incidental controls and methods of cooling are omitted from the drawing in the interests of simplicity.

Heavler intermediate fractions of the crude oil charge are withdrawn from fractionator 3 by way of line 35 containing valve 36 to pump 3T and discharged through line 3E containing valve 3S through line lili to heating coil El. Heating element 4l is arranged in a suitable furnace t2, whereby the products passing therethrough may preferably by heated to some temperature within the approximate range 900 to 1050 F. depending upon the boiling range and refractory properties of the material supplied thereto. The heated products are passed through line 43 containing valve M to catalytic reaction chamber 45. The pressure in this unit is preferably only slightly superatmospherlc since best results are usually obtained when granular catalysts are employed if the formation of hydrogen is not depressed by superimposed pressure and dehydrogenation reactions occur to increase the degree of unsaturation and hence the antiknock value of the nal product.

A number of catalysts may be used in the reaction chamber of this unit, the selection of any one depending upon numerous circumstances,-

such as the nature of the oil entering the unit and the availability and cost of the catalyst. The invention is not limited to the use of any particular catalyst, but some may be mentioned as being particularlyeicient such as, for example, composite catalysts consisting of mixtures of silica and alumina in varying proportions and produced by co-precipitation, successive precipitation or wet mixing of hydrated silica and hydrated alumina followed by exhaustive washing to remove occluded salts, calcining at moderate temperatures and sizing or pelleting to produce catalytic particles of a practical diameter. In some instances good results may7 be obtained by utilizing granular catalysts consisting of relatively inert and generally siliceous supports having deposited on their'surfaces and in their pores varying amounts of metal, metal oxides and some metal salts. Obviously, none of the materials will be exactly equivalent in their effects on the same or different charging stocks, and their selectlon is in any case a matter of expediency.

The total products from the catalytic reaction chamber pass through line 46 containing valve 4l into separator 48, wherefrom residual material is withdrawn through line t9 containing valve 50 for further treatment as will be subsequently described. Vaporous conversion products from separator 8 are passed through line 5! containing valve 52 into fractionator 53. This fractionator is again preferably operated to produce a gasoline boiling range material of at least 'I0 octane number, the vapors and fixed gases following line 54 containing valve 55 to condenser 5E, from which the condensed liquids and uncondensed gases pass through line 5T containing valve 58 to receiver 58. The `gas withdrawn at this point in the system through line 60 containing valve 6| may also be treated for the utilization of its oleiln content in admixture with gases withdrawn from line 3|, as previously mentioned. The gasoline products from the catalytic unit is withdrawn through line 62 containing valve 53 and blended with the gasoline produced at other points in the process.

Intermediate boiling range fractions from catalytic cracking are withdrawn from fractionator 53 through line 6i containing valve E5 to pump` 66 by means of which they may be returned through line 61 containing valve 68 to line Il and thence to heating coll 4l for further conversion. When itis not desired to return the intermediate fractions withdrawn from the lower portion of fractionator 53 to heating coil 4l for further conversion, it is within the scope oi.' the invention to commingle all or a portion o! this material with the residual liquid withdrawn from separator 8 through line 49, by well known means not shown, for further treatment as will be presently described.

In accordance with the invention the heavier fractions of the crude oil withdrawn from the lower portion of fractionator 3 through line 69 containing valve 'lll are commingled with the residual liquid from the reforming operation withdrawn from separator i9 through line 20 and with the residual liquid from the catalytic cracking operation withdrawn from separator. 48 through line 49. In a copending application I have' disclosed a process whereby a similar residual mixture may be flash distilled to produce specification fuel oil. With certain crude oils it would not be possible to produce specification fuel oil by ash distillation or stripping and I, therefore. subject this residual mixture to thermal cracking to produce either specification fuel oil or coke, while at the same time producing additional yields of gasoline of at least octane number.

Referring to the drawings, the commingled.

residual liquids are supplied to pump 1|. by means of which they are fed through line 12 containing valve 13 and line 'M to heating coil 15 disposed to receive heat from furnace 16.

Conditions employed in the thermal cracking unit are mildand of the order of 900 F. and 400 pounds per square inch. The heated products from heating element l5 pass through line 16 containing valve 1 1 to reaction chamber 18. The total cracked products pass through line 19 containing valve to a reduced pressure separator 8l which functions v to remove heavy residual products, while the uncondensed vapors are passed through line 82 containing valve 83k to fractionator 84. Fractionator 84 functions to produce Aan overhead gasoline of the required boiling range and antiknock value, the vapors of this gasoline plus incondensible gases pass through line 85 containing valve 86 and to condenser 81, from which condensed liquids and uncondensed gases follow line 88 vcontaining valve 89 to receiver 90 having a fixed gas release line 9| containing valve 92 and a gasoline draw line 93 containing valve 94.

As already specified at otherpoints, the gas mixture released from this receiver may be treated to polymerize their clef-lnic content by any method either thermal or catalytic and the gasoline withdrawn should have at least 70 octane number. Intermediate reflux condensate from fractionator 84 passes through line 95 containing valve 96 to recycle pump 91 by means of which it is fed through line 98 containing valve 99 and line 14 to heating coil 15 for further conversion.

The residual materials from separator 8|, which preferably operates at a pressure of .the order of 50 to 100 pounds per square inch, pass through line and, if of proper characteristics, may be withdrawn through line |0| containing valve |02 as specification fuel oil or, if unsatisfactory as specification fuel oil, may be supplied through line |03 containing valve |04 to flash or coke chamber |05. Chamber |05 may be operated to produce either specification fuel oil or coke. Any well known means for stripping the residual liquid therein to specification fuel oil such as steam, gases, closed heating coils, etc., may be employed.

When producing coke in chamber i 05 any means may be employed to eifect the coking of this residual material such as, for example, independently heating the residual liquid in a separate heating coil, the use of highly heated vapors or gases as a heat carrying medium, etc., may be employed. Drain line |06 containing valve |01 may be used for withdrawing specification iuel oil from this chamber or may be used for the introduction of steam, heat carrying medium or other materials when processing to coke. Vapors from chamber |05 pass through line |08 containing valve |09 to fractionator M0, which4 typifies any arrangement which will permit the productionu of a gas fraction containing all constituents not needed to give the required vapor pressure to the gasoline, these pounds per square inch.

tion was catalytically cracked in the presence of a granular catalyst comprising silica supporting about 10% of alumina, utilizing a` temperature of 950 F. and a pressure of 10= pounds per square inch. The residual liquid from all three operations was thermally cracked at a temperature of about 9309 F.'and a pressure of 350 When processing to specification fuel oil the following overall yields by volume may be obtained:

Percent (l) 72 octane number gasoline l 'I3 (2) Navy specification fuel oil 17 (3) Gas and loss 10 When processing to coke the following overall yields by volume may be obtained:

- Percent (l) 72 octane'number gasoline 76 (2) Coke, gas and loss 24 which comprises fractionating crude petroleum to produce overhead gasoline, light and heavy gases being withdrawn through line containing valve ||2, and a gasoline fraction which is withdrawn through line ||3 containing valve 4 and which preferably has the properties of at least 70 octane number as already specified. Heavy intermediate fractions may be withdrawn -from fractionator ||0 through line H5 containing valve ||6 to pump ||1 by means of which it may be returned through line ||8 containing valve ||9 to chamber |06. When these heavy intermediate fractions are suitable as cracking stock, it is within the scope of the invention to supply the same to the thermal cracking zone for additional conversion therein.

The foregoing description is a general outline of the invention and the following example isv given to show the character of the results obtainable in its practicable operation, although none of the data is introduced with the object of unduly limiting the broad scope of the invention.

intermediate fractions, and residuum, cooling, condensing' and collecting said overhead gasoline, thermally reforming said light intermediate fractions, catalytically cracking said heavy intermediate fractions, and thermally cracking said residuum together with residual liquids produced in the reforming 'and catalytic cracking operations to produce specification fuel oil.

2.1iV processfor treating crude petroleum which comprises fractionating said petroleum to produce overhead gasoline` of at least `70 octane number, light and heavy intermediate fractionsf and residuum, cooling, condensing and collecting said overhead gasoline, thermally reforming said light intermediate fractions to produce gasoline of at least 70 octane number, catalytically cracking said heavy intermediate fractions Ato produce gasoline of at least 70 octane number, and thermally cracking said residuum along with residual liquids produced in the reforming and catalytic cracking operations to producespeciflcation fuel oil. i

3. A process for treating crude petroleum which comprises fractionating said petroleum to produce overhead gasoline of at least 70 octane number, light and heavy intermediate fractions and residuum, cooling, condensing and collecting said overhead gasoline, thermally reforming said light intermediate fractions to produce gasoline of at least 70 octane number, catalytically cracking said heavy intermediate fractions to produce gasoline of at least 70 octane number, and thermally cracking said residuum along with residual liquids,produced in' the reforming and catalytic cracking operations to produce specification fuel' oil and gasoline of at least 70 octane number.

4. A- process for treating crude petroleum which comprises fractionating crude petroleum to produce overhead gasoline, light and heavy intermediate fractions, and residuum, cooling, condensingand collecting said overhead gasoline, thermally reforming said light intermediate fractions, catalyticaily cracking said heavy intermediate fractions and fractionating resultant 'vaporous products independently of said crude petroleum, and thermally cracking said residuum together with residual liquids produced in the reforming and catalytic cracking operations to produce coke.

5. A process for treating crude petroleum which comprises fractionatlng said petroleum to produce overhead' gasoline of atleast I0 octane number, light and heavy and residuum, cooling, condensing and collecting said overhead gasoline, thermally reforming said light intermediate fractions to produce gasoline of at least 70 octane number, catalytically cracking said heavy intermediate fractions to produce gasoline of at least 70 octane number and fractionating resultant vaporous products independently of said crude petroleum, and thermally ,cracking saidresiduum along with residual liquids produced in the reforming and catalytic cracking operations. to produce coke.

6. A process for treating crude petroleum which comprises fractionating said petroleum intermediate fractions l to produce overhead gasoline of at least 70 octane number, light and heavy intermediate fractions and residuum, cooling, condensing and collecting said overhead gasoline, thermally reforming said light intermediate fractions to produce gasoline of at least 'l0 octane number, catalytically cracking said heavy intermediate fractions to produce A gasolineA of at least '10 octane number and fractionating resultant vaporous products independently of, said crude petroleum, and thermally cracking said residuum along with residual liquids produced ln the reforming and catalytic cracking operations to produce coke and gasoline of at least 'I0 octane number.

7. A conversion process which comprises fractionating crude petroleum under substantially non-cracking conditions to form a light fraction containing low anti-knock gasoline components, an intermediate fraction consisting essentially of hydrocarbons heavier than gasoline, and topped crude, thermally reforming said light fraction, catalytically cracking said intermediate ,fraction and fractionating resultant vaporous products independently of said crude petroleum, combin` ing the topped crude with residual products of the thermal reforming and the catalytic cracking, and thermally cracking the resultant mixture.

l JEAN DELATTRE SEGUY. 

